The present invention relates to a method for creating digital video disks which are not susceptible to copying. Specifically, a system for creating mass copies of digital video disks is described from which commercially acceptable copies may not be made.
The explosion of digital data technology has produced a demand for mass marketed data mediums in the form of optical disks and magnetic tapes which include audio and video records, which are played on CD players and audio tape players. Digital video disks have stored thereon an optically encoded digital file of a video work including the program material divided into frames which is replayed by the user.
The illicit copying of such digital video disks is a significant problem for copyright owners. As one solution to this dilemma, it is possible to encrypt the digital data before recording the data on a digital master data recording which is used to make copies on a large scale. Even though the original master data recording is maintained secret, it is possible, sooner or later, using brute force techniques to discover a universal key needed to decrypt the data.
In the related field of maintaining computer software secret various techniques have been developed for protecting the software against unauthorized use. One common solution used to frustrate the unauthorized use and copying of computer software includes the provision of a hardware device mounted to the port of computer which executes the software. Unless the external hardware is present, a copy of the software is useless as execution will halt without the corresponding hardware device connected to the computer.
CD players and audio tape players, however, generally do not have the ability to provide such hardware security. The adaptation of these techniques to the protection of mass produced and distributed audio and video disks requires that a hardware device be provided for supplying keys to decrypt any encrypted data on the recorded mediums. To the extent that the discovery of the keys can be maintained secret, commercial copying of the works becomes unprofitable.